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95 Camry with low side in vacuum and high side at 85 me diagnose

Leggie on Mon August 26, 2013 12:42 PM User is offline

Year: 1995
Make: Toyota
Model: Camry
Engine Size: 2.5
Refrigerant Type: 134a
Ambient Temp: 75
Pressure Low: 28" vac
Pressure High: 85

I'm working on a 1995. It started with intermittently not blowing cold about a year ago but the pressures appeared normal.
Now the system is not working at all. System was evacuated, and recharged with 850g per factory specs.

I believe this compressor is the variable displacement type.

Vacuumed for 15 minutes,and 10 min rest did not locate leaks.

My experience with VD compressors is that can be quite evasive. They can be bad and still look normal and as a last resort, you replace the compressor and voila it works.

The low side hovers at about 60 psi while refrigerant is getting injected from tank and high side lingers around 80-90 psi.

Once the refrigerant tank is removed, low drops to 28" of vacuum, high doesn't move from 80 psi even with varying engine speed. There's neither heat rejection at the condenser nor refrigerant motion in receiver. I didn't feel any cooling in pipes leading to compressor and there is no abnormal noise.

My understanding was that restrictions on high side results in high pressure on high side, but Toyota service manual suggests expansion valve obstruction for a vacuum reading on low combined with low reading on high side.

Does this car use a variable displacement compressor?
How likely is it for the expansion valve to go bad while the compressor is still good? (could it be internal pressure regulator inside the compressor? ) How common is it for TXV to become completely obstructed that is not a result of secondary effect of compressor failure? I can only guess that the source of particles as being the receiver dryer disintegrating, but I don't know how common this is.

I don't like throwing parts at problems and I would like to diagnose it the best I can before taking the next step and I am trying to understand the cause of this failure..

thanks for your input.

Chick on Mon August 26, 2013 1:08 PM User is offlineView users profile

You have a restriction, possibly thedissicant inthe drier clogged the expansion valve..Take the line off the drier and you may see the junk going to the expansion that first and let us know what you find..hope this helps.. Your car uses a fixed displacement compressor denso I believe...

Email: Chick


Freedoms just another word for nothing left to lose

Edited: Mon August 26, 2013 at 2:29 PM by Chick

Leggie on Tue August 27, 2013 1:09 AM User is offline

I've always been told restricted high side (i.e. in receiver/TXV) causes high side pressure to skyrocket on fixed displacement system.

I believe that variable displacement systems usually use a passive valve that actuates swash plate to vary the displacement in response to try to maintain constant low pressure. When evaporator load is high, the vapor pressure increases which increases displacement and just the opposite when its low.

So, when high side is blocked, nothing feeds the low side which pulls a vacuum, which in turn puts the displacement to minimum thus reducing high side...

Does that seem about right?

Chick on Tue August 27, 2013 6:48 AM User is offlineView users profile

Pressure "skyrocketing" would depend on a lot of factors from where the blockage is to bad fans etc, but once the low side pulls into vacuum there is nothing to pump, the refrigerant in the system just pools in the condenser, drier etc.... Your car uses the Denso 10pa17C fixed displacement compressor...Hope this helps..

Email: Chick


Freedoms just another word for nothing left to lose

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